Indicia reading terminals for reading decodable indicia are available in multiple varieties. For example, minimally featured indicia reading terminals devoid of a keyboard and display are common in point of sale applications. Indicia reading terminals devoid of a keyboard and display are available in the recognizable gun style form factor having a handle and trigger button (trigger) that can be actuated by an index finger.
Indicia reading terminals having keyboards and displays are also available. Keyboard and display equipped indicia reading terminals are commonly used in shipping and warehouse applications, and are available in form factors incorporating a display and keyboard. In a keyboard and display equipped indicia reading terminal, a trigger button for actuating the output of decoded messages is typically provided in such locations as to either enable actuation by a thumb of an operator or in some cases also providing a handle and trigger button that can be actuated by the index finger.
Indicia reading terminals in a form devoid of a keyboard and display or in a keyboard and display equipped form are commonly used in a variety of data collection applications including point of sale applications, shipping applications, warehousing applications, security check point applications, and patient care applications, and personal use, common where keyboard and display equipped indicia reading terminal is provided by a personal mobile telephone having indicia reading functionality.
Some indicia reading terminals are adapted to read bar code symbols including one or more of one dimensional (1D) bar codes, stacked 1D bar codes, and two dimensional (2D) bar codes. Other indicia reading terminals are adapted to read optical character recognition (OCR) characters while still other indicia reading terminals are equipped to read bar code symbols, OCR characters, postal symbologies or other information bearing indicia.
Bar code symbols are typically disposed on a substrate such as paper. Recently, bar code symbols are now being displayed on a display screen. Attempts have been made to provide indicia reading terminals capable of reading bar codes on paper and bar codes displayed on a display screen. For example, one attempt includes the indicia reading terminals toggling back and forth between frames with and without the illumination on and each having custom fixed exposures.
There is a need for further image data collection, and in particular to devices and methods employing dual target auto exposure such as image sensor based indicia reading terminals.